
Chapter 4
PB
Measures of Dispersion
135
In case deviation is taken from the median, the above formula can be rearranged as
Median absolute deviation =
−
=
∑
(
i
n
1
In case deviation is taken from the mode, the above formula can be rearranged as
Mode absolute deviation =
−
=
∑
(
i
n
1
where (),( ),
xx xM
iidio
−− − are absolute deviations from mean, median, and mode,
respectively, and n is the number of items in a data series.
Mean absolute deviation is an absolute measure of dispersion. In this context, a relative meas-
ure, also known as coef cient of mean absolute deviation, is obtained by the following formula:
Coef cient of mean absolute deviation ...